Selective synthesis of hierarchical mesoporous spinel NiCo2O4 for high-performance supercapacitors

Hierarchical mesoporous spinel NiCo2O4 was synthesized by a facile hydrothermal method assisted by polyvinylpyrrolidone (PVP) and a post annealing treatment. The synthesized hierarchical mesoporous NiCo2O4 presents a hierarchical mesoporous structure with diameters of 5.0 and 25 nm, respectively. Compared to conventional flower-like NiCo2O4, the hierarchical mesoporous structured NiCo2O4 exhibits excellent supercapacitor performance. The specific capacitance can reach 1619.1 F g(-1) at a current density of 2.0 A g(-1). When the current density is increased to 10.0 A g(-1), a specific capacitance of 571.4 F g(-1) can be obtained. Furthermore, the hierarchical mesoporous structured NiCo2O4 presents excellent stability. The outstanding electrochemical performance of the hierarchical mesoporous NiCo2O4 reveals its potential to be a promising material for use in supercapacitors, and also inspires continued research on binary metal oxides as energy transformation materials.